https://leetcode.cn/problems/container-with-most-water/description/
//class Solution {
//public:
//    int maxArea(vector<int>& height) {
//        int ret = 0;
//        int left = 0;
//        int right = height.size() - 1;
//        while (left != right) {
//            int v = min(height[left], height[right]) * (right - left);
//            ret = max(ret, v);
//            if (height[left] < height[right]) {
//                left++;
//            }
//            else {
//                right--;
//            }
//        }
//        return ret;
//    }
//};

https://leetcode.cn/problems/happy-number/description/
//class Solution {
//public:
//    int SqortSum(int n) {
//        int sum = 0;
//        while (n != 0) {
//            int t = n % 10;
//            n /= 10;
//            sum += (t * t);
//        }
//        return sum;
//    }
//
//    bool isHappy(int n) {
//        int slow = n, fast = SqortSum(slow);
//        while (slow != fast) {
//            slow = SqortSum(slow);
//            fast = SqortSum(SqortSum(fast));
//        }
//        return slow == 1;
//    }
//};